Electric meter.



No. 796,038. PATBNTED AUG. 1, 1905.

' T.-DUNGAN.

' ELECTRIC METER. I APYPLIGATION FILED JULY 11, 1901. v

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UNITED STATES PATENT oEEIoE.

THOMAS DUNCAN, OF CHICAGO. ILLINOIS, ASSIGNOR TO DUNCAN ELEC- TRICMANUFACTURING COMPANY, OF LAFAYETTE, INDIANA.

ELECTRIC METER.

Specification of Letters Patent.

Patented Aug. 1, 1905.

Application filed Jilly 11, 1901. erial No. 67,814:-

To all whom it may concern:

Be it known that I, THoMAs DUNCAN, a citizen of theUnited States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Electric Meters, ofwhich the following is a full, clear, concise, and exact description,reference being had to the accompanying drawings, forming a part of thisspecification.

My invention relates to electric meters for measuring the load or energyin systems of electrical distribution, and has as its salient features,first, the provision of two cooperating step-by-step adjusting means forgoverning the torque in the meter by the introduction of resistance andvarying the number of effective turns in a meter-windingwhereby the rateof operation of the meter for a given load may be varied so that themeter may be caused to totalize at a rate according to the price agreedupon with the consumer; second,

' the provision of automatically-operated means for governing theoperation of the meter to decrease the rate of operation thereof as theload in the system increases, so that the consumer may have the benefitof a sliding discount, the discount increasing with the increase incurrent consumption.

That feature of my present invention employing two means forpreadjusting a fixed discount is of particular utility in connectionwith meters employing an auxiliary fieldwinding that acts to create astarting torque useful in assisting the meter on light loads and inovercoming friction. One of the said adjusting means comprises,preferably, a rheostat that may be placed in series with the artheseadjusting resistances may by their stepby-step ad ustment provide forfive, ten, fifteen, twenty, and twenty-five per cent. dis-v count. Oneconsumer may not be given any discount. His meter will then indicate thetrue reading in kilowatt-hours of the energy consumed. Another consumermay be given five per cent. discount. Supposing that he has consumed onethousand kilowatt-hours, his instrument will indicate a charge for ninehundred and fifty kilowatt-hours. Another consumer who uses ten thousandor more kilowatt-hours may be given ten per cent. discount, and for tenthousand kilowatt-hours consumed his meter will indicate a charge fornine thousand kilowatt-hours. By this arrangement the keeping ofaccounts is greatly simplified, as the consumers are charged accordingto the readings of their meters, each instrument then taking cognizanceof the particular consumers discount. As the discount is increased theadjusting resistance included in series with the armature and thestarting field-winding is also increased, whereby the volume of currentthrough the starting fieldwinding is decreased. To maintain a givenfield strength produced by the starting fieldwinding, I provide meanswhereby additional turns thereof are included in circuit as additionalsections of the said adjusting resistance are included in circuit, sothat the increased number of turns in the field-Winding compensates forthe decreased volume of the current flowing through the same.

That feature of my invention which relates to the automatic change inthe rate of speed of the meter is employed where the consumers are givena fluctuating discount in addition to the fixed predetermined discount,whereby the rate of operation of the counting-train per unit of load orenergy is decreased as the consumption of current increases. Thisfeature of the invention is preferably practiced by including a seconddiscount-adjusting resistance in series with the prediscount-adjustingre-.

is adapted to effect engagement between springs constituting theterminals of the various sections of the resistance when the current inthe system is within certain predetermined limits, whereby all of thisresistance is shunted from the armature. As the current in the systemexceeds a certain predetermined maximum, the core or armature isattracted to permit a separation between a number of terminal springscorresponding to the excess in current to introduce a correspondingamount of fluctuating resistance in the armature-circuit, therebydecreasing the torque of the instrument-and causing a reduced rate ofoperation of the measuring mechanism of the instrument per unit of loador energy.

I prefer to employ the means described, which causes a change in therate of operation of the counting mechanism by an adjustment of thetorque of the meter; but I do not wish to be limited to this means forvarying the rate of operation of the measuring mechanism, as otherinstrumentalities may be employed for accomplishing the same resultwithout departing from the spirit of the invention.

I will explain my invention more fully by reference to the accompanyingdrawings, in which- Figure 1 illustrates a system of direct-currentdistribution, the meter being diagrammatically indicated in elevation,the fluctuating discount resistance being excluded from circuit. Fig. 2is a view similar to Fig. 1, the meter-windings being morediagrammatically illustrated and the fluctuating discount resistancebeing shown totally included in the armature-circuit.

Like parts are indicated by similar characters of reference in bothviews.

I have illustrated a system of direct-cur rent distribution and acommutated motormeter; but the invention is equally applicable to othersystems of electrical distribution and to meters of other forms.

In each of the figures a generator 1 is illustrated that suppliescurrent to the transmis' sion-mains 2 2. These mains convey current totranslating devices, such as electric lamps ,3, that may be connected incircuit with supply-conductors 4 4. A meter 5 is associated with theconsumers supply-circuit4 4, the meter in this instance employing afield-winding divided into coils 6 6 in series with one of theconductors 4 and an armature 7 in bridge between the mains 4 4, acommutator 8, with brushes 9 9, being provided for including thearmature in circuit. The armature is mounted upon a shaft 10, at thelower part of which is a damping-disk 11, arranged within the fields ofthe permanent magnets 12 12 to secure requisite damping effect.

In order to adjust the torque of the meter to conform to the prearrangedcost of the current, I preferably include a resistance 13, that may betermed a prediscount resistance, in series with the armature, thisresistance being provided with a plurality of disto indicate variousdiscounts. A switch-arm 14 may be swung into engagement with any of thebuttons to include more or less of the resistance 13 in circuit with thearmature. If the consumer is to be charged at the highest rate, thecircuit conditions may be such that none of the resistance 13 should beincluded in circuit with the armature, whereby the greatest torque mayexist between the armature and field. If the consumer is to receive fiveper cent. discount, a certain section of the resistance may be includedin circuit by swinging the rheostat-arm 14 to the button marked 5F Ifthe consumer is to receive ten per cent. discount, the arm 14 may beswung to the button 10. Thus the torque of the meter may be readilyadjusted to cause the meter to indicate a quantity of energy for which afixed rate may be charged, the indicated quantity of energy being thesame as the actual quantity consumed where no fixed discount is allowedand less than the actual energy consumed according to the percentage ofdiscount.

here a supplemental starting field-winding, such as the winding 15, isincluded in series with the discount resistance, it is obvious that anincrease of the prediscount resistance would reduce the volume ofcurrent flowing through the auxiliary field-winding, whereby the fieldproduced by the auxiliary winding is reduced in effect, impairing theefficiency thereof, especially when the meter is to work on light loads.To obviate this difficulty, I provide supplemental turns for thesupplemental starting field wimling, which are added to the supplementalfieldwinding as the prediscount resistance is added, whereby acompensation is effected for a reduction in the volume of current, sothat a uniform magnetic field dueto the auxiliary winding is maintained.

A switch-arm 16 may be provided to engage with buttons that are markedto indicate the various discounts in a manner corresponding to themarking of the prediscount resistance. For example, if the consumer isto be allowed no discount no resistance 13 is preferably included incircuit, while the switcharm 16 is thrown to the button that indicatesno discount, whereby a minimum quantity of the auxiliary field-windingis included in the circuit. If the consumer is to be allowed lire percent. discount, the switch-arms 14 and 16 are thrown to thecorresponding buttons, whereby some of the resistance 13 is included inseries with the armature; but at the same time a corresponding increaseis effected in the auxiliary winding 15 to compensate for the reducedcurrent flowing through this winding.

To provide a fluctuating discount that may or may not be given inaddition to the discount aflorded by the resistance 13, I providecount-buttons that may be suitably marked 1 means preferably in the formof a torque-adteaoss i 3 justing resistance 17, having terminalcontactsprings 18. This resistance is preferably included in series withthe resistance 13 and the armature, in which case when the current inthe system is within the predetermined limits all of the resistance isshort-circuited, as illustrated in Fig. 1.

system is at the maximum, the resistance-ter- When the current in themeasuring mechanism per unit of energy or load in proportion to thecurrent in the system with the discount taken into consideration. Thecontrol of the resistance-terminals 18 is automatically eifected,preferably, by means of an electromagnet or solenoid 19, whose armatureor core 20 is provided with a spring 21, that holds the armature againstthe back-stop 22 during the time that thecur: rent in the system iswithin the limits that entitle the consumer to no sliding discount. Thisadjustment is illustrated in Fig. 1, all of the resistance 17being'shunted out of circuit by the electrical contact of all thesprings 18, which are thrust together by means of the armature 20 or anextensionthereof. The winding of the magnet is preferably included inseries with one of the main conductors 4.

When there is that current in the system for which the consumer isentitled to the greatest sliding discount, the solenoid-core is fullyattracted by its helix, the armature then being withdrawn fromengagement with the resistance-terminals 18, which thereupon separateand include the total resistance in circuit with the armature to producethe slowest rate of operation of the measuring mechanism per unit ofload or energy.

I have illustrated the resistance 17 as being designed to eflectasliding rate of discount of two, four, six, and ten per cent-that is, ifthere is a sufficient increase in current to provide for a two-per-cent.discount all but the upper terminal spring 18 are bunched together,leaving su'fficient resistance 17 in circuit to produce a readingdiscountedtwo per cent. If the current increases sufliciently further toa quantity where the consumer is entitled to four per cent. discount,all but the twoupper terminal springs 18 are bunched together, therebyincluding the two upper sections of the resistance 17 in circuit. Itwill be observed that the solenoid l9 constitutes a unitaryelectromagnetic means for changing the resistance 17.

I desirably vary the magnetizing effect of the coil 15 upon the armatureby the method disclosed; but I do not wishto be limited to this method.In my application, Serial No. 68,751, filed July 18, 1901, I havebroadly claimed the supplemental pressure-coil 15, as herein shown.

While I have herein shown and particularly described the preferredembodiment of my invention, I do not wish to limit myself to the preciseconstruction and arrangement as herein shown and particularly described;but,

Having thus described my invention, I claim as new and desire to secureby Letters Patent 1. The combination with a system of electricaldistribution, of a meter for measuring the load thereof, step-by-stepoperating means for changing the rateof operation of the measuringelement of the meter per unit of load or energy, and unitaryelectromagnetic means for operating the aforesaid means step by step todecrease the rate of operation of the said measuring mechanism upon an,in-

crease in current of the system, substantially as described.

2. The combination with a system of electrical distribution, of acommutated motor-meter for measuring the load thereof, a resistancedivided into sections,an electromagnetic mechanism supplied with currentfrom the system serving to include sections of the resistance in serieswith thearmature upon an increase in the current and to shunt the saidresistance from the armature-circuit upon a decrease in the current,whereby the measuring mechanism of the meter may be operated at afluctuating rate per unit of load or energy by a fluctuating current,substantially as described.

3. The combination with a system of electrical distribution, of a meterfor measuring the load thereof, step-by-step operating means forchanging the rate of operation of the measuring elernentof the meter perunit .of load or energy, unitary electromagnetic means for operating theaforesaid means step by step to decrease the rate of operation of thesaid measuring mechanism upon an increase in current of the system, andmeans for preventing a decreased rate of operation of the measuringmechanism per unit of load or energy until the current has reachedapredetermined value, substantially as described.

. 1. The combination with a system of electrical distribution, of acommutated motoruring mechanism of the meter may be operated at afluctuating rate per unit of load or energy by a fluctuating current,and means for'preventing the decreased rate of operation of themeasuring mechanism per unit of load or energy until the current hasreached a predetermined value, substantially as described.

5. The combination with a system of electrical distribution, of a meterreceiving current therefrom, an adjusting prediscount resistance incircuit with a winding of the meter to adjust the rate of speed of themeasuring mechanism per unit of load or energy, and means for varyingthe number of effective turns of the said winding to secure its propermagnetizing effect, substantially as described.

6. The combination with a system of electrical distribution, of a meterreceiving current therefrom, an adjusting prediscount resistance inseries with a winding of the meter to adjust the rate of speed of themeasuring mechanism per unit of load or energy, and means for varyingthe number of effective turns of the said winding to secure its propermagnetizing effect, substantially as described.

7 The combination with a system of electrical distribution, of a meterreceiving current therefrom, the said meter being provided with anauxiliary field-winding for producing starting torque, an adjustingprediscount resistance in circuit with another meter-winding and inseries with the said auxiliary winding to adjust the rate of speed ofthe measuring mechanism per unit of load or energy, and means forvarying the number of efiective turns of the said auxiliary winding tosecure its proper magnetizing effect, substantially as described.

8. The combination with a system of electrical distribution, of a meterreceiving current therefrom, the said meter being provided with anauxiliary field-winding for producing starting torque, an adjustingprediscount resistance in series with said auxiliary winding and anothermeter-winding to adjust the rate of speed of the measuring mechanism perunit of load or energy, and means for varying the number of effectiveturns of the said auxiliary winding to secure its proper magnetizingeffect, substantially as described.

9. The combination with a system of electrical distribution, of acommutated motormeter receiving current therefrom, the said meter beingprovided with an auxiliary [ieldwinding for producing starting torque.an adjusting prediscount resistance in circuit with the armature and inseries with the said auxiliary winding to adjust the rate of speed ofthe measuring mechanism per unit of load or energy, and means forvarying the number of effective turns of the said auxiliary winding tosecure its proper magnetizing effect, substantially as described.

10. The combination with a system of electrical distribution, of acommutated motormeter receiving current therefrom, the said meter beingprovided with an auxiliary iieldwinding for producing starting torque,an adjusting prediscount resistance in series with the armature and thesaid auxiliary fieldwinding to adjust the rate of speed of the measuringmechanism per unit of load or energy, and means for varying the numberof effective turns of the said auxiliary winding to secure its propermagnetizing efl'ect, substantially as described.

11. The combination with a system of electrical distribution, of a meterfor measuring the load thereof, a resistance divided into sections, anelectromagnetic mechanism supplied with current from the system servingto include sectionsof the resistance in series with the armature upon anincrease in the current and to shunt the said resistance from thearmature-circuit upon a decrease in the current, whereby the measuringmechanism of the meter may be operated at a fluctuating rate per unit ofload or energy by a fluctuating current, substantially as described.

12. In an electric meter, the combination with step-by-step means forchanging the rate of operation of the measuring element of the meter perunit of load or energy, of unitary electromagnetic step-by-stepoperating means for operating the aforesaid means step by step todecrease the rate of operation of the said measuring mechanism upon anincrease in the current measured, substantially as described.

13. In an electric meter, the combination with motor members therefor,of a commutator, resistances divided into sections, an electromagnetsupplied with current from the system serving to include sections of theresistance in series with the armature upon an increase in the currentand to shunt the said resistance from the armature-circuit upon adecrease in the current, whereby the measuring mechanism of the metermay be oper ated at a fluctuating rate per unit of load or energy by afluctuating current, substantially as described.

14:. In an electric meter, the combination with step-by-step means forchanging the rate of operation of the measuring element of the meter perunit of load or energy, of unitary electromagnetic step-by-stepoperating means for operating the aforesaid means step by step todecrease the rate of operation of the said measuring mechanism upon anincrease in the current of the system, and means for preventing thedecreased rate of operation of the measuring mechanism per unit of loador energy until the current has reached a predetermined value,substantially as described.

15. The combination with a system of electrical distribution, of a meterreceiving current therefrom, an adjusting prediscount resistance incircuit with a field-winding of the meter to adjust the rate of speed ofthe measuring mechanism per unit of load or energy, and means'forvarying the magnetic influence of the said winding, substantially asdescribed.

16. The combination with a system of electrical distribution, of a meterreceiving current therefrom, an adjusting prediscount resistance inseries with a field-winding of the meter to adjust the rate of speed ofthe measuring mechanism per unit of load or energy, and means forvarying the magnetic influence of the said winding, substantially asdescribed.

17. The combination with a system of electrical distribution, of a meterreceiving current therefrom, the said meter being provided with anauxiliary field-winding for producing starting torque, an adjustingprediscount resistance in circuit with another meter-winding and incircuit with the said auxiliary winding to adjust the rate of speed ofthe measuring mechanism per unit of load or energy, and means forvarying the magnetic influence of the said auxiliary winding,substantially as described.

18. The combination with a system of electrical distribution, of a meterreceiving current therefrom, the said meter being provided with anauxiliary field-winding for producing starting torque, an adjustingprediscount resistance in series with said auxiliary Windingand anothermeter-winding, to adjust the rate of speed of the measuring mechanismper unit of load or energy, and means for varying the magnetic influenceof the said auxiliary winding, substantially as described.

19. The combination with a system of elec trical distribution, of acommutated motormeter receiving current therefrom, the said meter beingprovided with an auxiliary fieldwinding for producing starting torque,an adjusting prediscount resistance in circuit with the armature and inseries with the said auxiliary winding to adjust the rate of speed ofthe measuring mechanism per unit of load or energy, and means forvarying the magnetic influence of the said auxiliary winding,substantially as described.

4 20. The combination with a system of electrical distribution, of acommutated motor- In witness whereof I hereunto subscribe my name this23d day of May, A. D. 1901.

THOMAS DUNCAN.

Witnesses:

GEORGE L. ORAGG, HERBERT F. OBERGFELL

